Biomedical subjects

N Terada

Publications and source records attributed to N Terada.

At least 199 records · Page 11Linked to original sources

PubMed1996

The effect of anti-VLA-4 monoclonal antibody on eosinophil accumulation and leukotriene production in nasal mucosa.

Eosinophil derived leukotrienes and platelet activating factor are known to cause nasal swelling. Toxic proteins induce nasal hyperreactivity to non-specific stimuli including histamine. Recent studies strongly suggest that very late activation antigen-4 (VLA-4) on the eosinophil surface plays a prominent role in the recruitment of eosinophils from blood vessels and eosinophil locomotion in inflammatory tissues. To test this hypothesis, we examined the effect of a monoclonal antibody (mAb) to VLA-4 on eosinophil accumulation in nasal mucosa after antigen challenge in a guinea pig model. Here we have demonstrated that the mAb depressed the eosinophil accumulation in nasal mucosa. In addition, we have shown that this mAb also inhibited eosinophil activation and leukotriene production. Our results raise a possibility that eosinophils might be activated during the journey from bloodstream to inflammatory tissues by the adhesion to endothelial cells and fibronectin. VLA-4 might act as a signalling as well as an adhesion receptor on eosinophils.

Animals↗

PubMed1996

[The effect of histamine on the adhesion of endothelial cells to eosinophils].

Recent studies have revealed that eosinophils and eosinophil-derived mediators strongly contribute to the onset of nasal swelling and nasal hyperreactivity. The effect of histamine on the adhesion of endothelial cells to 35S-labeled eosinophils and on eosinophil transendothelial migration was investigated. Human microvascular endothelial cells were isolated and cultured from the mucosa of the inferior turbinates of patients with nasal allergy. Histamine caused dose-related enhancement of adhesiveness to eosinophils. Incubation of endothelial cells treated with 10(-5)M and 10(-4)M histamine increased adhesion to eosinophils by a mean of 56.4% (p < 0.05) and 66.0% (p < 0.05), respectively. When eosinophils were incubated with histamine, they did not induce any increase in adhesion to endothelial cells. Preincubation of endothelial cells with anti-ELAM-1 significantly inhibited histamine-induced adhesion, whereas anti-ICAM-1 and anti-VCAM-1 had no inhibitory effect. Histamine did not increase eosinophil transendothelial migration. Histamine is known to be vasoactive, mediating vasodilation and plasma extravasation. In addition, the results of this study raise the possibility that histamine promotes eosinophil adhesion to endothelial cells by increasing ELAM-1 molecules on endothelial cells and promotes nasal inflammatory and allergic reactions.

Adolescent↗

PubMed1996

Three-dimensional ultrastructure of in situ membrane skeletons in human erythrocytes by quick-freezing and deep-etching method.

The erythrocyte membrane skeleton is a network of some structural proteins, principally composed of spectrin, actin and protein 4.1, which is also attached to the cytoplasmic surface of the lipid membrane. The purpose of the present review is to describe the three dimensional ultrastructure of in situ membrane skeletons in human erythrocytes. The in situ membrane skeletons are densely organized, and the spectrin itself has a property of extension or contraction with reacting the external mechanical forces. The lengths between the intersections are changed according to the mechanical strength, and also vary even in one erythrocyte. To clarify the in situ organization of membrane skeletons, the quick freezing and deep-etching method should be used for fresh unfixed erythrocytes because of their fragility during preparation steps.

Cytoskeletal Proteins↗

PubMed1995

Selective activation of c-Jun kinase mitogen-activated protein kinase by CD40 on human B cells.

The B cell surface antigen receptor, surface IgM (sIgM), is involved in B cell activation and proliferation. CD40 is involved in regulating IgE production and B cell survival. Cross-linking of B cell sIgM activates the Ras/Raf/p42erk2 pathway. In contrast, ligation of CD40 by antibody or soluble gp39 (CD40 ligand) leads to activation of the c-Jun kinase (JNK)/stress-activated protein kinase pathway. JNK/stress-activated protein kinase activation correlated with the stimulation of MEK kinase activity. CD40 does not activate the p42erk2 pathway, and sIgM fails to regulate the JNK/stress-activated protein kinase pathway in B cells. Thus, two important cell surface receptors involved in controlling specific B cell response differentially regulate sequential protein kinase pathways involving different members of the mitogen-activated protein kinase family. Anti-CD40 also rescued B cell apoptosis induced by anti-IgM. CD40 ligation did not affect the sIgM stimulation of p42erk2 activity. Conversely, sIgM ligation did not influence CD40 stimulation of JNK/stress-activated protein kinase. These results suggest that independent, parallel protein kinase response pathways are involved in the integration of sIgM and CD40 control of B cell phenotype and function.

Antibodies↗

PubMed1995

Overexpression of the PRAD1 oncogene in a patient with prolymphocytic leukemia with t(11;14)(q13;q32).

Prolymphocytic leukemia (PLL) was diagnosed by morphologic and immunophenotypical studies in a 72-year-old Japanese man. Massive splenomegaly was present but lymphadenopathy was minimal in this case. Chromosomal analysis of peripheral mononuclear cells showed t(11;14)(q13;q32) in all metaphases examined, except for one normal karyotype. Northern blot analysis of RNA prepared from leukemic cells obtained from the patient revealed overexpression of the PRAD1/cyclin D1 proto-oncogene, which has not been described previously in patients with PLL.

Aged↗

PubMed1995

Rapamycin inhibits ribosomal protein synthesis and induces G1 prolongation in mitogen-activated T lymphocytes.

We investigated the effects of rapamycin (RAP) on cell cycle progression and protein synthesis in mitogen-activated primary T lymphocytes. Stimulation of resting human T lymphocytes with phorbol ester and calcium ionophore rendered cells capable of initiating DNA synthesis within 30 h; roughly 60% of the cells entered the first G2/M phase of the cell cycle within 96 h. Addition of RAP delayed the entry into S phase by 9 h, although a similar percentage (approximately 50%) of cells entered the first G2/M phase and proliferated. On this basis, we concluded that RAP primarily induced a G1 prolongation without blocking cell cycle progression. Addition of the co-mitogens to resting T lymphocytes up-regulated the translation of ribosomal protein mRNA concurrent with activation of p70s6k. RAP inhibited this translational up-regulation of ribosomal protein mRNA as well as the activation of p70s6k without affecting translation of nonribosomal protein mRNA. RAP also prevented the synthesis and accumulation of ribosomal proteins. Further, this failure to increase ribosomal proteins, which probably reflects the failure to increase numbers of ribosomes, resulted in suppression of the synthesis of total cellular protein and a delay in the escalation of cell size. RAP-treated cells eventually initiated DNA synthesis when cell size became equivalent to that of the control cells entering S phase of the cell cycle. Thus, inhibition of protein synthesis caused by the primary inhibition of ribosomal protein mRNA translation probably explains the effect of RAP on cell cycle progression of mitogen-activated resting T lymphocytes.

Amino Acid Sequence↗

PubMed1995

Effects of iron-depletion on cell cycle progression in normal human T lymphocytes: selective inhibition of the appearance of the cyclin A-associated component of the p33cdk2 kinase.

Iron removal by the chelating-agent deferoxamine (DFO) arrests cell cycle progression of activated human T cells in late G1 phase, before the G1/S border. The effects of the drug on molecules that regulate progression through the cell cycle were defined. DFO (10 mumol/L) inhibited induction of transcription of the cdc2 gene, but had no effect on accumulation of cdk2, cdk4, or interleukin (IL)-2-transcripts. No detectable p34cdc2 protein accumulated, but synthesis of the p33cdk2 protein was begun. It accumulated to normal levels during the first 20 to 30 hours of incubation in the presence of DFO. Furthermore, p33cdk2 was activated as an H1 histone kinase. As active p33cdk2 primarily represents complexes of the p33 protein with cyclin E or cyclin A, the effects of DFO on these cyclins were examined. Although the induction of synthesis and early accumulation of cyclin E and cyclin E-associated kinase activity appeared normal, the appearance of cyclin A and cyclin A-associated kinase activity were inhibited by DFO. However, the production of cyclin A mRNA appeared to be normal in the presence of DFO. A major effect of DFO in blocking cell cycle progression may be mediated through inhibition of the appearance of cyclin A protein and, therefore, a major component of p33cdk2 activity. The results also indicate that the p33cdk2/cyclin E activity produced in the presence of DFO was not sufficient for completion of the G1 phase of the cell cycle.

CDC2 Protein Kinase↗

PubMed1995

Symmetry of the activation of cyclin-dependent kinases in mitogen and growth factor-stimulated T lymphocytes.

The entry of resting T cells into the G1 phase of the cell cycle after stimulation by mitogens is controlled by a series of biochemical events that are independent of growth factors. These events follow the initial signals stimulated through the engagement of the T-cell receptor and include activation of the cyclin-dependent kinases Cdk6, Cdk4, and Cdk2, as well as a transient phosphorylation of the retinoblastoma gene product (p110Rb) by one or several of these proteins. A progression signal such as that delivered by interleukin-2 then induces a second phase of Cdk6, Cdk4, and Cdk2 activation, along with sustained phosphorylation of p110Rb in the activated T cells. This second signal is required to carry the cells into the S phase and beyond. Quantitative and qualitative differences in the expression and activity of these proteins may be critical to maintain the delicate balance that is necessary to ensure the normal progression of T cells through the cell cycle.

Cell Cycle↗

PubMed1995

Nerve growth factor induces activation of MAP-kinase and p90rsk in human B lymphocytes.

A previous report from this laboratory demonstrated that human B lymphocytes expressed nerve growth factor (NGF) receptors on their surface. On the basis of NGF enhancement of B cell proliferation these receptors are presumed to be functional. We have now characterized one of the signaling pathways that NGF may utilize in the functional activation of B lymphocytes. Stimulation of three different human B-lymphoblastoid cell lines with NGF induced the tyrosine phosphorylation and activation of the p42erk-2 isoform of MAP-kinase (MAPK). In addition, NGF induced shifts in the mobility of p90 ribosomal S6 kinase (p90rsk) on immunoblots and increased p90rsk kinase activity in immunoprecipitates. NGF-induced shifts in p90rsk mobility displayed similar dose and time kinetics as NGF-induced MAPK activation. Activation of both MAPK and p90rsk occurred with doses of NGF as low as 400 pg/ml. Preincubation of NGF with anti-NGF Ab inhibited NGF-induced activation of MAPK and p90rsk. These results demonstrate that the interaction of NGF with its receptor on human B cells results in the stimulation of major components of the signaling pathway also initiated by NGF-receptor ligation in cells of neuronal origin.

B-Lymphocytes↗

PubMed1995

Platelet activating factor activates MAPK and increases in intracellular calcium via independent pathways in B lymphocytes.

Platelet activating factor (PAF)-stimulation of human B-lymphoblastoid cells results in the activation of microtubule associated protein 2-kinase (MAPK) and increases in intracellular calcium. Although increases in intracellular calcium induce MAPK activation in these cells, PAF can stimulate MAPK activation in the absence of detectable changes in intracellular calcium concentrations ([Ca2+]i). Treatment of the LA350 B-lymphoblastoid cell line with either pertussis toxin (PT) or cholera toxin (CT) blocked PAF-induced changes in [Ca2+]i. However, only PT blocked PAF-induced activation of MAPK as determined by shifts in the mobility of MAPK on immunoblots. In support of this finding, only PT but not CT blocked PAF-induced phosphorylation and activation of p90rsk, an event thought to be distal to MAPK activation. These results suggest that the PAF receptor is mediating MAPK activation through pathways separate from those mediating increases in intracellular calcium.

B-Lymphocytes↗

PubMed1995

Apoptosis of cultured mouse luteal cells induced by tumor necrosis factor-alpha and interferon-gamma.

BACKGROUND: Macrophages and T lymphocytes have been identified in the regressing corpus luteum, and they are thought to participate in structural luteolysis (destruction and removal of luteal cells). Since these cells produce cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), we investigated the effects of these two cytokines on death of luteal cells in vitro. METHODS: Mouse luteal cells were cultured in serum-free medium with TNF-alpha at 0, 500, 1,000, 3,000, or 5,000 U/ml in the presence or absence of IFN-gamma at 1,000 U/ml for 3 or 6 days. Then, for estimation of the actions of these cytokines on induction of luteal cell death, we determined the number of viable cells, the percentage of fragmented DNA in total DNA extracted from cultured cells, and the percentage of cells with fragmented DNA in their nuclei by the trypan blue exclusion test, the sensitive micromethod for DNA assay, and the in situ DNA 3' end labeling method, respectively. DNA fragmentation was also analysed by agarose gel electrophoresis, and cultured cells were examined by electron microscopy. RESULTS: On day 3 of culture, IFN-gamma alone at 1,000 U/ml or TNF-alpha alone at 500-5,000 U/ml did not decrease the number of viable cells, but a combination of IFN-gamma (1,000 U/ml) and TNF-alpha (5,000 U/ml) did. On day 6, IFN-gamma alone at 1,000 U/ml or TNF-alpha alone at 500, 1,000 and 3,000 U/ml did not decrease the number of viable cells, whereas TNF-alpha alone at 5,000 U/ml did, and combinations of IFN-gamma and TNF-alpha at 1,000, 3,000, and 5,000 U/ml decreased the number of viable cells in proportion to the concentration of TNF-alpha. On days 3-6 of culture, combinations of IFN-gamma and TNF-alpha that decreased the number of viable cells also increased the percentages of fragmented DNA in total DNA of cultured luteal cells and the percentages of luteal cells with fragmented DNA in their nuclei. Agarose gel electrophoresis of fragmented DNA showed a ladder-like pattern, and electron microscopic examination showed luteal cells with the characteristics of apoptosis. CONCLUSIONS: The presence of IFN-gamma modulates the ability of TNF-alpha to induce a reduction in the number of viable cells, although TNF-alpha alone at high concentrations can induce a reduction in the number of viable cells.

Animals↗

PubMed1995

Control of cell cycle entry and progression in mitogen-stimulated human B lymphocytes.

Tonsillar B lymphocytes were stimulated to proliferate by the mitogenic combination of phorbol dibutyrate and ionomycin. Progression through the cell cycle was monitored by measurements of cellular DNA and RNA content using flow cytometry. Changes in surface expression of class II MHC antigens and CD20 antigen were also monitored as early parameters of B lymphocyte activation and cell cycle progression. The results showed that about 60% of the population synchronously entered and progressed through the cell cycle. The transition from the resting state, signaled by increased RNA content, occurred about 12 to 24 hr after stimulation; S phase entry occurred at about 36 hr. Small, variable populations of cells appeared to be unresponsive to the stimuli, either because they were "preactivated" before in vitro stimulation or were already dying. The kinetics of appearance and accumulation of several cell cycle regulated/regulatory proteins were followed by immunoblotting. The proliferating cell nuclear antigen (PCNA) cyclin A and p33cdk2 proteins were either absent or present in very low amounts in resting cells and first became detectable in increased amount beginning at about 24 hr after stimulation; increased p34cdc2 protein was not detected until about 36 hr. Increased cellular content and phosphorylation of the p110Rb protein was already obvious by 24 hr after stimulation. The effects of several immunosuppressive agents were examined using purified B cells. Both cyclosporin A and an FK506 analogue were shown to inhibit proliferation of B lymphocytes, at the low doses also inhibitory to T cells.

Antigens, CD↗

PubMed1995

Differential regulation of the synthesis and activity of the major cyclin-dependent kinases, p34cdc2, p33cdk2, and p34cdk4, during cell cycle entry and progression in normal human T lymphocytes.

Three major cyclin-dependent kinases, p34cdc2, p33cdk2, and p34cdk4 were examined in normal human T cells stimulated to enter the cell cycle in vitro. None of the three genes was expressed in resting T cells. Transcripts form the cdk4 and cdk2 genes were detectable as early as 3 and 8 hr after stimulation, respectively, whereas cdc2 gene transcripts were not detectable until about 24 hr, shortly before S phase entry. Immunoblot analysis showed that resting T cells contained little p34cdk4, no p34cdc2, and a low level of p33cdk2 protein. Increased amounts of p34cdk4, p33cdk2, and p34cdc2 proteins were seen at about 7, 10, and 30 hr after stimulation, respectively. Immunoprecipitates of each of the kinases were assessed for histone H1 kinase activity. Activity due to p33cdk2 first became detectable in mid-G1 phase and increased dramatically after entry into S phase. Active p34cdc2 kinase was not detected until about 40 hr after stimulation, about 10 hr after the first appearance of the protein. Immunoprecipitates of p34cdk4 possessed almost no H1 histone kinase activity; however, activity was detected as early as 10 hr after cell activation when a protein (p60Rb) derived from the retinoblastoma susceptibility gene product was used as substrate. Cells were synchronized about the G1/S and G2/M borders by aphidicolin and nocodazole. Cells arrested prior to S-phase contained high levels of active p33cdk2 and essentially no active p34cdc2, despite the fact that large amounts of both proteins were present. Cells arrested by nocodazole had high levels of active p34cdc2 and greatly reduced levels of p33cdk2 kinase activity. The results suggest that the major role for the p34cdc2 kinase is at mitosis, whereas that for p33cdk2 is in late G1 and/or S phase. The p34cdk4 protein, present in aphidicolin-blocked cells, was nearly absent from cells arrested at the G2/M border; however, kinase activity was low in cells blocked at both points, suggesting that the major role for p34cdk4 may be in G1 phase.

CDC2 Protein Kinase↗

PubMed1995

Growth factors as mediators of androgen action during the development of the male urogenital tract.

Studies on the developing prostate and SV suggest that androgens act via mesenchymal AR to elicit synthesis and secretion of various autocrine and paracrine factors that regulate epithelial and stromal growth and differentiation. Clearly, the global regulation of epithelial growth and ductal branching morphogenesis is a complex multifactorial process involving the interplay of many diffusible factors (both positive and negative regulators), extracellular matrix molecules, cell-surface receptors for growth factors, receptors for extracellular matrix molecules, and matrix-degrading enzymes. Future progress will certainly be dependent upon the utilization of appropriate, biologically relevant models to examine the respective roles of various growth factors in the growth and development of androgen target organs.

Androgens↗

PubMed1995

Inhibitory effects of suramin on androgen-dependent and -independent growth of neonatal mouse seminal vesicles in vitro.

The effects of suramin on the growth of seminal vesicles (SVs) of neonatal mice were investigated in vitro. SVs from 0-day-old male mice were cultured in serum-free chemically defined medium supplemented with 5 alpha-dihydrotestosterone (DHT, 10(-8) M) and insulin (10 micrograms/ml), alone and in combination. Prior to culture, SVs from 0-day-old mice had no epithelial branches. SVs cultured in medium with DHT formed numerous epithelial branches, while epithelial branching did not occur in SVs cultured without DHT. The addition of suramin (0.2 mM) to medium containing DHT inhibited the formation of epithelial branches almost completely. Removal of suramin from the medium on days 2, 4, and 6 of culture initiated the formation of epithelial branches. Suramin (0.2 mM) reversibly decreased 3H-thymidine-labeling indices (3H-LI) of both epithelium and mesenchyme of SVs cultured in medium with DHT plus insulin or DHT alone during 8 days of culture. Suramin also decreased 3H-LI of both epithelium and mesenchyme of SVs cultured in medium with insulin alone. The present study indicates that suramin reversibly inhibits not only androgen-dependent but also androgen-independent growth and ductal branching morphogenesis of neonatal mouse SVs.

Androgens↗

PubMed1995

Vesnarinone inhibits nucleoside and nucleobase transport.

Vesnarinone is a novel synthetic oral inotropic agent that has been successfully used for treatment of patients with congestive heart failure. In addition to its cardiotonic activity, the drug has been proposed to have mild cytostatic and anti-HIV-1 effects. We have observed that vesnarinone profoundly inhibits radiolabeled thymidine and uridine incorporation into cells despite its modest inhibitory effect on DNA synthesis, RNA synthesis or cell proliferation. Here we demonstrate that vesnarinone inhibits both nucleoside and nucleobase transport in mammalian cells. This pharmacological action may be involved in some of its multiple biological effects.

Adenine↗

PubMed1995

Cytotoxic actions of cytokines on cultured mouse luteal cells are independent of nitric oxide.

We investigated the cytotoxic effects of various cytokines secreted by macrophages or T lymphocytes on luteal cells, and the role of nitric oxide (NO) produced by luteal cells in cytotoxic actions of cytokines. Mouse luteal cells were cultured in serum-free medium with interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) or interleukin-1 beta (IL-1 beta) alone, or with various combinations of these cytokines for 6 days. Cytotoxic actions of cytokines and NO production by luteal cells were evaluated by number of viable cells and the amount of nitrite and nitrate (stable metabolites of NO) in medium, respectively. IFN-gamma (1000 U/ml), TNF-alpha (3000 U/ml), or IL-1 beta (30 U/ml) alone, and the combination of TFN-alpha and IL-1 beta (10 U/ml) did not decrease number of viable cells and was without effects on NO production. The combination of IFN-gamma and IL-1 beta (10 U/ml) also did not decrease the number of viable cells, while it increased NO production a little but significantly. Combinations of INF-gamma and TNF-alpha, and IFN-gamma, TNF-alpha and IL-1 beta (10 U/ml) markedly decreased number of viable cells. The combination of IFN-gamma and TNF-alpha increased NO production a little but significantly, and the combination of three cytokines (IFN-gamma, TNF-alpha, and IL-1 beta) caused a greater increase in NO production. An NO synthase inhibitor, L-NG-monomethy-L-arginine (0.5 mM) or aminoguanidine (0.5 mM) abolished increases in NO production induced by combinations of IFN-gamma and TNF-alpha, and IFN-gamma, TNF-alpha and IL-1 beta completely without effects on number of viable cells. The present results indicate that combinations of cytokines including IFN-gamma and TNF-alpha induce death of cultured mouse luteal cells, and that the cytotoxic actions of these cytokines are independent of NO production by luteal cells.

3-Hydroxysteroid Dehydrogenases↗

PubMed1995

Danazol concentrations in ovary, uterus, and serum and their effect on the hypothalamic-pituitary-ovarian axis during vaginal administration of a danazol suppository.

OBJECTIVE: To determine danazol concentrations in the ovary, uterus, and serum during daily vaginal administration of a danazol suppository and to examine its effect on the hypothalamic-pituitary-ovarian axis. DESIGN: Sampling of tissues after vaginal or oral administration of danazol and sampling of blood during control and danazol-administration menstrual cycles. SETTING: Outpatient volunteers and inpatients at a public hospital. PARTICIPANTS: Thirty patients who were to undergo hysterectomy and oophorectomy because of uterine leiomyoma and eight regularly menstruating volunteers. INTERVENTIONS: Danazol was administered as a vaginal suppository (100 mg) or orally (400 mg). MAIN OUTCOME MEASURE: Danazol concentrations in the ovary, uterus, and serum, and serum E2 and P levels. RESULTS: Danazol concentrations in the ovary and uterus after daily vaginal administration of a suppository containing 100 mg danazol were comparable to those after daily oral administration of 400 mg danazol, but the serum danazol concentration was much lower. Menstrual cycle patterns of serum E2 and P levels were normal during daily vaginal administration of a danazol suppository. CONCLUSION: Daily administration of a suppository containing 100 mg danazol produces high ovarian and uterine concentrations but low serum concentrations, and no effect was detected on the hypothalamic-pituitary-ovarian axis.

Adult↗